Seat base for chair



FIG. 1 is a perspective view of a seat base for chair showing my newdesign;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left elevational view thereof; the opposite side being amirror image of the shown; and,

FIG. 5 is a top plan view thereof.

The ornamental design for seat base for chair, as shown and described.